Unveiling the Secrets of the Stars

Hot objects emit radiation (light). The hotter they are the more radiation they emit and the higher energy of that radiation. This means that all hot objects show a characteristic pattern of light emission called black-body radiation. BLACKBODY RADIATION

Stellar spectra show how much light is emitted at different colors The shape of the curve is called a blackbody curve: BLACKBODY CURVES

Where do you think the peak would be for an O star? What about an M star? BLACKBODY CURVES FOR STARS

Black body radiation is directly related to temperature It also depends ONLY on temperature So we can look at a star’s color and tell its temperature From this and its brightness, we can tell how far away it is We can also tell how big it is A LITTLE GOES A LOOOONG WAY

COLOR AND TEMPERATURE

LET’S TRY IT!